Does the modern concept of 'best medical therapy' render carotid surgery obsolete?
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Angioplasty, Balloon↗
Biomedical subjects
A R Naylor
Publications and source records attributed to A R Naylor.
Systematic review of randomized controlled trials of patch angioplasty versus primary closure and different types of patch materials during carotid endarterectomy.
BACKGROUND: Patch angioplasty during carotid endarterectomy (CEA) may reduce the risk for perioperative or late carotid artery recurrent stenosis and subsequent ischemic stroke. We performed a systematic review of randomized controlled trials to assess the effect of routine or selective carotid patch angioplasty compared with CEA with primary closure, and the effect of different materials used for carotid patch angioplasty. METHODS: Randomized trials were included if they compared carotid patch angioplasty with primary closure in any patients undergoing CEA or use of one type of carotid patch with another. RESULTS: Thirteen eligible randomized trials were identified. Seven trials involving 1281 operations compared primary closure with routine patch closure, and 8 trials with 1480 operations compared different patch materials (2 studies compared both). Patch angioplasty was associated with a reduction in risk for stroke of any type (P = .004), ipsilateral stroke (P = .001), and stroke or death during both the perioperative period (P = .007) and long-term follow-up (P = .004). Patching was also associated with reduced risk for perioperative arterial occlusion (P = .0001) and decreased recurrent stenosis during long-term follow-up (P < .0001). Seven trials that compared different patch types showed no difference in the risk for stroke, death, or arterial recurrent stenosis either perioperatively or at 1-year follow-up. One study of 180 patients (200 arteries) compared collagen-impregnated Dacron (Hemashield) patches with polytetrafluoroethylene patches. There was a significant increase in risk for stroke (P = .02), combined stroke and transient ischemic attack (P = .03), and recurrent stenosis (P = .01) at 30 days, and an increased risk for late recurrent stenosis greater than 50% (P < .001) associated with Dacron compared with polytetrafluoroethylene. CONCLUSIONS: Carotid patch angioplasty decreases the risk for perioperative death or stroke, and long-term risk for ipsilateral ischemic stroke. More data are required to establish differences between various patch materials.
Angioplasty↗
Carotid endarterectomy for the symptomatic patient: thinking beyond "stenosis > 70%".
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Carotid Stenosis↗
A critical review of the role of carotid disease and the outcomes of staged and synchronous carotid surgery.
Few subjects are as enduring as the management of patients with combined carotid and cardiac disease. This paper reviews the available evidence supporting and refuting the role of carotid artery disease in the pathophysiology of stroke after coronary artery bypass grafting surgery and analyzes the results of systematic reviews of staged and synchronous carotid reconstruction. The available data suggest that only about 40% of strokes (at most) could be directly attributable to ipsilateral carotid artery disease. The rate of death and stroke following staged or synchronous carotid surgery in all published series was 6% and 9%, respectively. Unfortunately, natural history data are inadequate to determine whether a policy of prophylactic carotid endarterectomy reduces the risk of stroke after cardiac surgery.
Carotid Artery Diseases↗
The excess of strokes in female patients after CEA is due to their increased thromboembolic potential--analysis of 775 cases.
INTRODUCTION: Women suffer an excess of complications following arterial surgery, including an increased stroke risk following CEA. In order to investigate this further we studied men and women's thromboembolic potential following CEA. METHOD: Analysis of prospectively collected data on 775 consecutive CEAs performed between October 1995 and October 2001, to identify the number of microembolic events detected following CEA. RESULTS: Overall women had a 2.2 fold increase in the number of postoperative emboli detected (95% CI 1.2-3.3). Of those patients with significant numbers of postoperative emboli (>25), 68% were female against 22% for men (p=0.009). In order to prevent progression onto postoperative thrombotic stroke 9.7% of women were treated with intravenous Dextran-40 therapy, as opposed to only 2.7% of men (p=0.013). There were no significant differences between men and women's preoperative risk factors and/or factors relating to their operation. CONCLUSION: It is possible that women's excess of postoperative complications following arterial surgery is related to their apparent increased thromboembolic potential following acute arterial injury.
Aged↗
Early and late outcome after carotid artery bypass grafting with saphenous vein.
OBJECTIVES: This study was undertaken to determine outcome and durability of internal carotid artery bypass grafting with saphenous vein. METHODS: Data for 50 patients undergoing serial clinical and ultrasound surveillance were collected prospectively and analyzed retrospectively. RESULTS: Bypass grafting was performed in 50 patients between 1995 and 2002, the commonest reasons being excessive endarterectomy zone thinning or penetrating atheroma (n = 22), severe internal carotid artery coiling above the endarterectomy zone (n = 14), and patch infection (n = 5). Perioperative mortality was 2%, and death and stroke rate was 6%. Perioperative complications were associated with complex cardiovascular events, including hemorrhage after prosthetic patch infection, on-table thrombosis after endarterectomy, and synchronous carotid artery-cardiac reconstruction. One patient had a late ipsilateral stroke (10 months; normal scan). Cumulative stroke-free survival at 3 years (including operative events) was 91%. Cumulative freedom from recurrent stenosis greater than 70% or occlusion was 86% at 1 year and 83% at 3 years. Severe recurrent stenosis or occlusion developed in 7 patients, within 9 months of surgery in 6 patients and with 18 months in 1 patient. Angioplasty was performed without complication (no protection device, no stent) in 5 patients, 3 of whom required repeat angioplasty on at least one further occasion. CONCLUSIONS: In common with venous conduits elsewhere, carotid artery bypass grafting with saphenous vein is associated with a high incidence of early graft stenosis. The long-term stroke risk, however, is low. Carotid artery bypass grafting is a safe and durable alternative when endarterectomy would prove hazardous or inadvisable, but regular surveillance is necessary.
Blood Vessel Prosthesis Implantation↗
The acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in vascular patients.
OBJECTIVE: the aim of this study was to establish at which point during a hospital admission MRSA acquisition occurs in vascular patients. METHOD: a consecutive series of 100 patients undergoing arterial surgery were screened for MRSA carriage on admission to hospital, on exit from theatre, on discharge from ITU, weekly whilst an inpatient and on hospital discharge. Screening was with moistened swabs from nose, throat, perineum and open wounds that were pooled for microbiological culture. RESULTS: four patients (4%) screened positive for MRSA on admission to hospital. Of the remaining 96, 16 (17%) acquired MRSA during their hospital stay as follows: exit from theatre, one; exit from ITU, six; on the ward postoperatively, nine. Comparing MRSA acquisition (n=16) with non acquisition (n = 80) the following characteristics were noted, length of stay 16 (4-66) vs 7 (2-50) days (Mann-Whitney p < 0.001); admission to ITU 13/16 vs 46/80 (Fishers chi-squared p = 0.10); length of ITU stay 3 (1-20) vs 3 (1-14) days (Mann-Whitney p = 0.41). Frequent hospital attendance, age, emergency admission, diabetes or renal failure were not commoner in those with MRSA acquisition. CONCLUSIONS: these data indicate that 4% of patients undergoing arterial surgery are pre-existing carriers of MRSA. Length of hospital stay is the single most important determinant of MRSA acquisition.
Adult↗
A systematic review of outcomes following staged and synchronous carotid endarterectomy and coronary artery bypass.
OBJECTIVES: to determine the overall cardiovascular risk for patients with combined cardiac and carotid artery disease undergoing synchronous coronary artery bypass (CABG) and carotid endarterectomy (CEA), staged CEA then CABG and reverse staged CABG then CEA. DESIGN: systematic review of 97 published studies following 8972 staged or synchronous operations. RESULTS: mortality was highest in patients undergoing synchronous CEA+CABG (4.6%, 95% CI 4.1-5.2). Reverse staged procedures (CABG-CEA) were associated with the highest risk of ipsilateral stroke (5.8%, 95% CI 0.0-14.3) and any stroke (6.3%, 95% CI 1.0-11.7). Peri-operative myocardial infarction (MI) was lowest following the reverse staged procedure (0.9%, 95% CI 0.5-1.4) and highest in patients undergoing staged CEA-CABG (6.5%, 95% CI 3.2-9.7). The risk of death+/-any stroke was highest in patients undergoing synchronous CEA+CABG (8.7%, 95% CI 7.7-9.8) and lowest following staged CEA-CABG (6.1%, 95% CI 2.9-9.3). The risk of death/stroke or MI was 11.5% (95% CI 10.1-12.9) following synchronous procedures versus 10.2% (95% CI 7.4-13.1) after staged CEA then CABG. CONCLUSIONS: 10-12% of patients undergoing staged or synchronous procedures suffered death or major cardiovascular morbidity (stroke, MI) within 30 days of surgery. Overall, there was no significant difference in outcomes for staged and synchronous procedures and no comparable data for patients with combined cardiac and carotid disease not undergoing staged or synchronous surgery.
Carotid Stenosis↗
Seizures after carotid endarterectomy: hyperperfusion, dysautoregulation or hypertensive encephalopathy?
OBJECTIVES: Presentation, management and outcome following seizure after carotid endarterectomy (CEA). MATERIALS AND DESIGN: Prospective audit. RESULTS: Eight patients (0.8%) suffered a seizure (three bilateral) <30 days following 949 CEAs. Seizure was not associated with age, gender or presentation. Seven were treated hypertensives but four had labile BP pre-operatively. Five had severe bilateral carotid disease and four had vertebral/subclavian stenoses. Six had a >50% drop in middle cerebral artery blood flow velocity (MCAV) with clamping. Only three had >100% increase in MCAV with flow restoration. Five required treatment for post-operative hypertension. Two suffered seizures <36 hrs of CEA, the remainder were at 3-8 days. All eight had significantly elevated blood pressure at onset of seizures. Four underwent immediate MCAV monitoring and each was elevated. Emergency CT scanning/autopsy showed normal scans (n = 3), white matter oedema (n = 3), oedema and diffuse haemorrhage (n = 1), intracranial haemorrhage (n = 1). Seven developed a post-ictal neurological deficit (stroke = 5, TIA = 2). Overall, two patients either died or suffered a disabling stroke. CONCLUSIONS: Post-CEA seizure was associated with adverse outcome. Most were labile hypertensives with severe bilateral carotid/vertebral disease. MCAV changes suggested poor collateral recruitment, but no consistent pattern of early hyperperfusion emerged. It remains uncertain whether high MCAVs and severe hypertension after seizure onset are cause or effect. Clinicians treating these patients in acute medical units were generally unaware of the "post-CEA hyperperfusion syndrome" and tended to treat the hypertension less aggressively.
Adult↗
The physiological effects of elevated intra-abdominal pressure following aneurysm repair.
OBJECTIVES: Elevated intra-abdominal pressure (IAP) may cause widespread organ dysfunction (abdominal compartment syndrome) through effects on the respiratory, cardiac, renal and gastro-intestinal systems. The aim of this study was to document IAP following aneurysm surgery, and to determine the effect of IAH on outcome. DESIGN: Prospective observational study. SETTING: University Hospital. SUBJECTS: The patient cohort comprised 75 patients undergoing infra-renal aneurysm repair (53 non-ruptured [40 conventional--1 death, 13 endovascular] and 22 conventionally repaired ruptured AAA--8 deaths). IAP was quantified by bladder manometry at the termination of the procedure and at 24 h intervals in patients who remained intubated. Physiological indices of organ function were recorded. Statistical analysis utilized the unpaired t-test, Fischer's exact test and Pearson's correlation. RESULTS: IAP was significantly higher at abdominal closure following ruptured aneurysm repair (15.4 mmHg [SE 1.6]) than conventional (10.5 [0.89]) or endovascular elective repair (6.4 [1.0]) of non-ruptured AAA. The sensitivity and specificity of IAP to predict subsequent mortality was analysed using a receiver characteristic operating curve. This analysis demonstrated that a cut off of 15 mmHg was the most useful for indicating patients at risk (sensitivity 0.66, specificity 0.79). Physiological indices of organ dysfunction (pH[P = 0.027], base excess [p = 0.005], peak inspiratory pressure [p = 0.0015], CVP and urine output [p = 0.0029]) were significantly impaired in patients with IAP > or = 15 mmHg, in comparison to patients with lower pressures. IAP correlated significantly with indices of cardiac (CVP p = 0.038), respiratory (PaO2/FiO2, p = 0.026), and renal function (urine output p = 0.046). CONCLUSIONS: These data suggest that the management of IAH may have a role following repair of ruptured AAA. High intra-abdominal pressures rarely complicate elective or endovascular aneurysm repair.
Abdomen↗
Overview of the principal results and secondary analyses from the European and North American randomised trials of endarterectomy for symptomatic carotid stenosis.
OBJECTIVES: Review of the primary results and secondary analyses from the European Carotid Surgery Trial (ECST) and the North American Symptomatic Carotid Endarterectomy Trial (NASCET). DESIGN: Review of 48 ECST and NASCET papers. RESULTS: The simple assumption that all patients with a symptomatic stenosis >70% benefit from CEA is untenable. Approximately 70-75% will not have a stroke if treated medically. The ECST and NASCET have identified subgroups that should have expedited investigation and surgery (male sex, age >75 years, 90-99% stenosis, irregular plaque, hemispheric symptoms, recurrent events for >6 months, contralateral occlusion, multiple co-morbidity). Accordingly development of local protocols for patient selection/exclusion should involve surgeons and physicians and take account of the local operative risk. The ECST and NASCET have also shown that the ubiquitous "string sign" is not associated with a high risk of stroke, and emergency CEA is unnecessary. CONCLUSIONS: Surgeons must quote their own results and be aware that a high operative risk reduces long-term benefit. Accordingly, in those centres with a higher operative death/stroke rate, some "lower risk" patients should probably be considered for best medical therapy alone. It is hoped that pooling of the ECST and NASCET databases will enable more definitive guidelines to be developed regarding who benefits most from CEA.
Aged↗
Infection of an internal carotid artery plaque with vancomycin resistant enterococcus.
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Aged↗
Does the risk of post-CABG stroke merit staged or synchronous reconstruction in patients with asymptomatic carotid disease?
The management of patients with combined carotid and coronary artery disease remains controversial, largely because of a lack of high quality natural history studies in patients with asymptomatic carotid disease undergoing isolated coronary artery bypass surgery. To date, practice ranges from never recommending additional intervention to a more aggressive policy of prophylactic carotid endarterectomy. For surgeons in the latter group, the only remaining debate is whether CEA should be staged or synchronous. This paper reviews the rationales and available evidence for managing the cardiac patient with asymptomatic carotid disease and is largely based on the findings of 2 recently published systematic re-views on the subject. These reviews suggest that a reappraisal of practice is necessary before the indiscriminate implementation of carotid angioplasty further complicates interpretation of the already poor quality data available.
Carotid Stenosis↗
Matrix metalloproteinases and atherosclerotic plaque instability.
BACKGROUND: There is growing interest in the role of matrix metalloproteinases in atherosclerosis. Excessive tissue remodelling and increased matrix metalloproteinase activity have been demonstrated during atherosclerotic plaque disruption, a frequent predeterminant of ischaemic cardiac events and stroke. These enzymes represent a potential target for therapeutic intervention to modify vascular pathology. METHODS: The core of this review is derived from a Medline database literature search. RESULTS: There is convincing evidence of increased matrix metalloproteinase activity during acute plaque disruption. Evidence for an imbalance promoting increased matrix degradation is less well documented. However, studies of matrix metalloproteinase inhibition in models of vascular disease suggest a potential therapeutic benefit. CONCLUSION: In vivo studies of matrix metalloproteinase inhibition are required to study the potential for reversal or deceleration of the excessive tissue remodelling that accompanies acute plaque disruption.
Arteriosclerosis↗
Prosthetic patch infection after carotid endarterectomy.
OBJECTIVES AND DESIGN: prospective audit of the management and outcome of prosthetic patch infection after carotid endarterectomy (CEA) at Leicester Royal Infirmary plus review of the literature. RESULTS: 8/936 CEA patients (0.85%) developed a prosthetic patch infection. Responsible organisms included MRSA (n=3), Staphylococcus epidermidis(n=2), haemolytic Streptococcus (n=1), Staphylococcus aureus(n=1) and Pseudomonas (n=1). Early wound complications preceded 4/5 infections presenting within 9 weeks of surgery. In addition to systemic antibiotics and debridement, management included patch removal and: (i) carotid ligation (n=3), vein patch repair (n=1), vein bypass (n=3). One patient had antibiotic irrigation of the in-situpatch. No patient died, one suffered a disabling postoperative stroke and two had temporary cranial nerve injuries. Including this series, a literature review identified 43 prosthetic patch infections, 91% culturing Staphylococci or Streptococci. Cumulative freedom from perioperative stroke/death or re-infection was 65% at 2 years. Patients treated by patch excision and autologous venous reconstruction had the best outcome with a cumulative freedom from perioperative stroke/death or re-infection of 91% at 2 years. CONCLUSION: prosthetic patch infection after CEA is rare. This study emphasises the importance of close surveillance of early wound complications. Surgical decision-making, especially the safety of carotid ligation, was facilitated by access to transcranial Doppler.
Bacterial Infections↗
Variation in surgical and anaesthetic technique and associations with operative risk in the European carotid surgery trial: implications for trials of ancillary techniques.
OBJECTIVES: several ancillary surgical techniques, such as shunting and patching, are used in association with carotid endarterectomy. However, the balance of risks and benefits of these techniques is uncertain because of the lack of large randomised controlled trials (RCTs). To assess the potential for further trials, we studied the variation in use of these techniques by surgeon and by country in the European Carotid Surgery Trial (ECST). METHODS: use of each ancillary technique was assessed by surgeon and by country. For each technique, the relationships between the use of the technique and baseline patient characteristics, use of other techniques, and the 30-day operative risk of stroke and death were determined. RESULTS: there was considerable variation between surgeons in the use of ancillary operative techniques both within (p<0.001 for shunting and patching), and between countries (p<0.001 for shunting and patching). Some surgeons used techniques selectively, and so the characteristics of patients differed depending on which techniques were used. Use of each technique was also significantly associated with the use of other techniques. Multiple regression analysis, taking into account all these factors, found no statistically significant associations between operative risk and the use of shunting, patching, intra-operative EEG monitoring, or type of anaesthetic. The only surgical technique significantly associated with an increased operative risk was not using intra-operative anticoagulation (hazard ratio=2.33, 95% CI=1.4-4.2). Other factors associated with an increased risk were an operation time of less than 1 h, or greater than 1.5 h, and the surgeons' subjective assessment that the operation was difficult. CONCLUSIONS: in the ECST, operative risk was more closely related to patient characteristics, length of surgery, and the surgeons' perception of the difficulty of the operation, than to the use of particular ancillary operative techniques. The considerable variation between surgeons, and between countries, in the use of ancillary techniques is in keeping with the lack of convincing data from RCTs, and suggests that there should be sufficient uncertainty to make large pragmatic trials possible.
Aged↗
Carotid artery disease and stroke during coronary artery bypass: a critical review of the literature.
OBJECTIVES: to determine the role of carotid artery disease in the pathophysiology of stroke after coronary artery bypass (CABG). DESIGN: systematic review of the literature. RESULTS: the risk of stroke after CABG was 2% and remained unchanged between 1970-2000. Two-thirds occurred after day 1 and 23% died. 91% of screened CABG patients had no significant carotid disease and had a <2% risk of peri-operative stroke. Stroke risk increased to 3% in predominantly asymptomatic patients with a unilateral 50-99% stenosis, 5% in those with bilateral 50-99% stenoses and 7-11% in patients with carotid occlusion. Significant predictive factors for post-CABG stroke included; (i) carotid bruit (OR 3.6, 95% CI 2.8-4.6), (ii) prior stroke/TIA (OR 3.6, 95% CI 2.7-4.9) and (iii) severe carotid stenosis/occlusion (OR 4.3, 95% CI 3.2-5.7). However, the systematic review indicated that 50% of stroke sufferers did not have significant carotid disease and 60% of territorial infarctions on CT scan/autopsy could not be attributed to carotid disease alone. CONCLUSIONS: carotid disease is an important aetiological factor in the pathophysiology of post-CABG stroke. However, even assuming that prophylactic carotid endarterectomy carried no additional risk, it could only ever prevent about 40-50% of procedural strokes.
Carotid Artery Diseases↗
Combined therapy with clopidogrel and aspirin significantly increases the bleeding time through a synergistic antiplatelet action.
OBJECTIVE: Many thromboembolic events occur in patients taking aspirin. Dual therapy with aspirin and clopidogrel may prove effective at reduction of thromboembolic complications. However, the extent to which these two drugs interact may significantly increase the risk of bleeding in open surgery. Because of the increased use of combination antiplatelet therapy in populations with significant atherosclerotic disease, this risk needs to be evaluated by the assessment of the combined effect in vivo of clopidogrel and aspirin on bleeding time and platelet function. OUTCOMES: In seven healthy subjects, addition of low dose clopidogrel (2 x 75 mg) to aspirin (150 mg) therapy significantly increased bleeding time (from 7.6 +/- 3.4 minutes to 17.5 +/- 8.6 minutes; P <.05), with concomitant falls in adenosine diphosphate (ADP)-induced platelet fibrinogen binding and aggregation (P <.05). Increasing the dose of clopidogrel to 300 mg increased bleeding time (to 24.9 +/- 8.5 minutes; P <.05) without significant additional platelet inhibition. There was considerable variability in the individual subject platelet response to the lower dose of clopidogrel. Those patients with the highest ADP response at baseline had the least response, and subjects with a weak response to ADP at baseline achieved maximal platelet inhibition with the low dose of clopidogrel. CONCLUSION: The increases in bleeding times should be considered in combination antiplatelet therapy in patients who undergo open vascular surgery.
Adult↗